Git Rebase vs Git Merge: Which One Should You Use and When?

Harish M

Git Rebase vs Git Merge: Which One Should You Use and When?

A detailed guide to understanding the differences between Git rebase and merge, helping you make informed decisions for your version control workflow.

Understanding the Basics

Git Merge

Before Merge
main     A---B---C
              \
feature        D---E

After Merge
main     A---B---C---F
              \     /
feature        D---

Key Characteristics

• Creates a new merge commit

• Preserves complete history

• Non-destructive operation

• Maintains branch context

• Safe for shared branches

Git Rebase

Before Rebase
main     A---B---C
              \
feature        D---E

After Rebase
main     A---B---C
                \
feature         D'---E'

Key Characteristics

• Linear project history

• Clean commit history

• Rewrites commit history

• No merge commits

• Better for local branches

Key Differences

1. History Structure

Merge

• Preserves branch history

• Shows when branches were created

• Maintains context of parallel development

• Creates a merge commit

Rebase

• Creates linear history

• Hides when branches were created

• Appears as if work was done sequentially

• No merge commits

2. Commit History

Merge

# Merge commit message
Merge branch 'feature' into main

# Commit history
A---B---C---F (main)
     \     /
      D---E (feature)

Rebase

# Commit history
A---B---C---D'---E' (main)

3. Use Cases

When to Use Merge

• Public/shared branches

• Preserving branch history

• Complex feature branches

• Team collaboration

When to Use Rebase

• Local feature branches

• Clean project history

• Before merging to main

• Individual development

Implementation Examples

Git Merge

# Basic merge
git checkout main
git merge feature

# Merge with no fast-forward
git merge --no-ff feature

# Merge with specific strategy
git merge -X theirs feature

Git Rebase

# Basic rebase
git checkout feature
git rebase main

# Interactive rebase
git rebase -i HEAD~3

# Rebase with conflict resolution
git rebase --continue
git rebase --abort

Best Practices

Merge Best Practices

1. When to Use

   • Merging feature branches

   • Preserving history

   • Team collaboration

   • Public repositories

2. How to Use

   • Use --no-ff for feature branches

   • Write clear merge messages

   • Resolve conflicts carefully

   • Keep branches up to date

Rebase Best Practices

1. When to Use

   • Local development

   • Before merging to main

   • Cleaning up commits

   • Maintaining linear history

2. How to Use

   • Don't rebase public history

   • Use interactive rebase

   • Test after rebasing

   • Keep backups

Common Scenarios

Scenario 1: Feature Development

# Using merge
git checkout main
git merge feature

# Using rebase
git checkout feature
git rebase main
git checkout main
git merge feature

Scenario 2: Updating Feature Branch

# Using merge
git checkout feature
git merge main

# Using rebase
git checkout feature
git rebase main

Scenario 3: Cleaning Up Commits

# Interactive rebase
git rebase -i HEAD~3

# Squash commits
pick abc1234 First commit
squash def5678 Second commit
squash ghi9012 Third commit

Potential Issues

Merge Issues

1. Merge Conflicts

   • Complex resolution

   • Multiple conflict points

   • History preservation

   • Team coordination

2. History Clutter

   • Merge commits

   • Branch complexity

   • Hard to follow

   • Visual noise

Rebase Issues

1. History Rewriting

   • Lost context

   • Force push needed

   • Team coordination

   • Backup required

2. Conflict Resolution

   • Sequential conflicts

   • Multiple resolutions

   • Complex scenarios

   • Time-consuming

Team Guidelines

When to Choose Merge

1. Team Collaboration

   • Shared branches

   • Public repositories

   • Team coordination

   • History preservation

2. Project Requirements

   • Complex features

   • Long-lived branches

   • Multiple developers

   • Release management

When to Choose Rebase

1. Individual Work

   • Local development

   • Feature branches

   • Code cleanup

   • History maintenance

2. Project Standards

   • Linear history

   • Clean commits

   • Code review

   • Quality control

3. Advanced Techniques

Merge Strategies

# Recursive merge
git merge -X recursive feature

# Octopus merge
git merge feature1 feature2

# Ours/Theirs
git merge -X ours feature
git merge -X theirs feature

Rebase Techniques

# Interactive rebase
git rebase -i HEAD~3

# Rebase with autosquash
git rebase -i --autosquash HEAD~3

# Rebase with preserve-merges
git rebase -p main

Decision Framework

Choose Merge When

• Working on shared branches

• Preserving branch history

• Complex feature development

• Team collaboration

Choose Rebase When

• Working on local branches

• Maintaining clean history

• Before merging to main

• Individual development

Conclusion

Both merge and rebase are valuable tools in Git. The choice depends on:

• Team workflow

• Project requirements

• History preferences

• Collaboration needs

• Development style

Next Steps

1. Evaluate your workflow

2. Set team guidelines

3. Practice both methods

4. Monitor effectiveness

5. Adjust as needed

   

   Resources

   1. Git Documentation

   2. Git Merge Strategies

   3. Git Rebase Documentation

   4. Atlassian Git Tutorial

Citations

1. Pro Git Book

2. GitHub Flow

3. Git Workflows

4. Git Best Practices